DESIGN OF INNER AND OUTER ROLLER BUCKWHEAT THRESHER AND FIELD TEST

Abstract

Aiming at the problems of large loss rate and high damage rate during buckwheat threshing, an inner and outer roller buckwheat thresher was designed. The device is mainly composed of an inner roller and an outer roller, the inner roller is a rod-tooth combination roller, and the outer roller is a grid roller, the inner and outer rollers can be rotated independently. The outer roller is supported on the friction wheels and the supporting wheels, and driven to rotate by the friction wheel transmission system. The compression device is installed at the top to prevent the outer roller from slipping during the rotation. During working, the materials enter between the inner and outer rollers and the separation of grains and stems under the brushing and kneading action of the inner and outer rollers takes place. In order to push the materials between the inner and outer rollers smoothly, a double spiral blade type screw feeding device was designed. By establishing a mathematical model of material pushing, the screw feeding device has a material conveying speed of 1.87 m/s and a conveying capacity of 4.29 kg/s. In order to study the threshing performance, the threshing device was installed on the basis of the Kubota 688 tracked type combine to complete a prototype of a tracked buckwheat combination harvester. Field tests show that the grain impurity rate is 6.50%, the grain damage rate is 1.42%, the threshing loss rate is 0.25%, the cleaning loss rate is 1.01%, the direct loss rate of the header is 2.43%, and the total machine harvest loss rate is 3.69% at the working speed of 0.53 m/s and the feeding rate of 0.41 kg/s. The test results provide a basis for the improvement of buckwheat mechanized harvesting machinery.